An interventional study of Voluntary Apnea in Healthy Vollunteer and Apnea, sponsored by Cliniques universitaires Saint-Luc- Université Catholique de Louvain. Recruiting at 1 site in Belgium. Open to participants aged 18 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-20.
Sponsored by Cliniques universitaires Saint-Luc- Université Catholique de Louvain · Not applicable, Interventional, and Other
Pulse oximeters estimate arterial oxyhaemoglobin saturation (SaO₂) from photoplethysmographic signals recorded at peripheral sites (usually the fingertip), thus measuring the peripheral oxygen saturation (SpO₂). They are ubiquitous in emergency medicine because they offer a non-invasive, continuous measure of oxygenation and can alert clinicians to impending hypoxaemia, both during procedures such as rapid sequence intubation or sedation, or for continuous monitoring of patients. However, the accuracy of SpO₂ is often assumed to be instantaneous. This assumption is particularly hazardous during critical events involving rapid desaturation and resaturation. In such situations clinicians use SpO₂ readings to decide when to stop an apnea period during laryngoscopy and commence reoxygenation. If there is a delay between actual arterial desaturation and the displayed SpO₂, the clinician may not recognise hypoxaemia in time or may resume ventilation too late.
1,417 studies on the registry are indexed under Apnea; 152 are open to participants now.
This study's planned enrollment of 100 is above the median of 51 across 962 interventional studies indexed under Apnea.
Browse Apnea studies →Cliniques universitaires Saint-Luc- Université Catholique de Louvain is the lead sponsor of 348 studies on the registry; 62 are open to participants now.
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Exclusion Criteria:
After a 5-minute resting period, two pulse oximetry sensors will be placed simultaneously: a finger sensor and an ear sensor (earlobe). Baseline parameters will be recorded. The apnea protocol will consist of a maximal inspiration followed by voluntary breath-holding. Throughout the procedure, oxygen saturation (SpO₂), heart rate, and perfusion index will be continuously recorded until the values return to baseline. The monitor screens will be video-recorded to allow precise temporal analysis of events (onset of apnea, resumption of breathing, desaturation, nadir, and resaturation). After a further 5-minute resting period, the procedure will be repeated a second time.
Diagnostic Test: Voluntary Apnea
Two pulse oximetry sensors (finger and earlobe) will be simultaneously applied, and baseline oxygen saturation (SpO₂), heart rate, and perfusion index will be recorded. The participant will then perform two voluntary apnea tests, during which these parameters will be continuously monitored to assess the timing of apnea, desaturation, nadir, and resaturation.
Evaluation of SpO₂ Resaturation Following Voluntary Apnea
To characterize the temporal behavior of a modern finger pulse oximeter during voluntary apnea in healthy volunteers, with a particular focus on the delay (in seconds) between physiological reoxygenation and displayed SpO₂ (Time interval in seconds between the first breath following apnea and the first increase in SpO2.)
Time frame: From enrollment to the end of the inclusion, estimated at approximately 10 months from the start of enrollment
Comparison of SpO₂ Temporal Parameters Between Finger and Ear Sensors
Saturation sensors will be placed on the ears and fingers of healthy volunteers. Saturation parameters will be recorded from both sensors and compared with the SpO2 saturation level (baseline SpO2): * Time (in seconds) between the onset of apnea and a decrease of ≥ 2% from baseline SpO2 * Time (in seconds) between the onset of apnea and the lowest SpO2 observed before the start of resaturation * Variable describing whether the SpO2 nadir (the lowest value) occurs before or after the resumption of ventilation
Time frame: From enrollment to the end of the inclusion, estimated at approximately 10 months from the start of enrollment
Quantification of SpO₂ Measurement Delay Between Measurement Sites
To quantify the magnitude of the SpO₂ measurement delay (in seconds) between the two measurement sites during the reoxygenation phase.
Time frame: From enrollment to the end of the inclusion, estimated at approximately 10 months from the start of enrollment
Assessment of Intra-Individual Measurement Variability
To assess intra-individual variability in key measurements (focus on the delay in seconds between physiological reoxygenation and displayed SpO2) across repeated apnea tests (2 different apnea)
Time frame: From enrollment to the end of the inclusion, estimated at approximately 10 months from the start of enrollment
Evolution of the Perfusion Index (PI) during Apnea and Reoxygenation by finger/auricular pulse oximeter
To describe changes in the perfusion index (PI in %) during apnea and reoxygenation. Baseline PI (%) will be recorded at finger and auricular sites in healthy volunteers over time in seconds. Minimum PI during apnea, magnitude of PI change during apnea, PI recovery time (in seconds) after rebreathing.
Time frame: From enrollment to the end of the inclusion, estimated at approximately 10 months from the start of enrollment
Physiological Factors Associated with SpO₂ Response Delay
To explore physiological factors associated with delayed SpO₂ response (in seconds), including individual characteristics and baseline hemodynamic parameters (BMI in kg/m\^2, medical history, chronic treatments).
Time frame: From enrollment to the end of the inclusion, estimated at approximately 10 months from the start of enrollment
Started Aug 2026 (actual). Primary completion is estimated for Feb 2027, 5 months after the start.
Of 296 non-industry interventional studies with no phase under Apnea, half reached primary completion within 27 months of starting (the median), counting those still running; a quarter within 12 and three quarters within 48. This study's planned 5 months is below that.
Counting every sponsor, half of 354 studies reached it within 23 months; a quarter within 11 and three quarters within 45.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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